1. Field of the Invention
The present invention relates to an image reading device having a prescanning function of reading an original in advance and a main scanning function of again reading the original after the prescanning, an image reading method applied to the image reading device, and a storage medium. More particularly, the invention relates to an image reading device which can be applied to a sheet feeding scanner for reading an original by moving it, a scanner in which an original is accommodated within an original-holder and is read together with the original-holder, or the like, and which is suitable when it is intended to assuredly receive an image from within a reading range set after prescanning by correcting the set reading range, an image reading method applied to the image reading device, and a storage medium.
2. Description of the Related Art
In conventional image reading devices, such as sheet feeding scanners and the like, having a prescanning function, in contrast to fixed-original scanners in which a scanning operation is performed by fixing an original, an image on an original is read by moving the original, a reading range in main scanning is assigned after prescanning via a display unit, the original is again set, and main scanning in which the original is read within the assigned reading range is performed. In image reading devices of a type in which a scanning operation is performed while accommodating an original in an original-holder, the original is accommodated in the original-holder and is scanned together with the original-holder.
FIGS. 7A-7D are diagrams, each illustrating an operation of reading an original in a conventional original reading device. In FIG. 7A, there are shown an original to be read 71, and an area A indicating a reading range assigned after prescanning. FIG. 7B illustrates a state in which the set position of the original 71 has laterally shifted to the left, the original 71 has shifted to the right in an original-holder (not shown), or the reading range has shifted to the right. An area B indicates a read range. FIG. 7C illustrates a state in which, when driving and feeding the original 71 to a reading position during main scanning, the original 71 has shifted in a longitudinal direction, or the original 71 within the original-holder has shifted upwardly within the original-holder. An area C indicates a read range. FIG. 7D illustrates a state in which, since the original 71 has not been uniformly driven during main scanning, the original 71 has been obliquely driven or the original 71 within the original-holder has inclined. An area D indicates a read range.
The above-described conventional approach has the following problems. In conventional image reading devices, such as sheet feeding scanners and the like, since a reading range at main scanning is assigned after prescanning, and main scanning in which the assigned range is read is performed after again setting an original, it is necessary to set the original twice in order to perform one image receiving operation. Since, as is shown in FIGS. 7A-7D, the position of the original changes every time the original is set, the set reading range differs, in some cases, from the actual receiving range.
Furthermore, since the surface state of the original is not constant, the frictional force between the driving member and the original changes due to dust and the like adhering to the original-driving roller of the image reading device, thereby producing, in some cases, slip of the original when driving the original. As a result, as shown in FIGS. 7A-7D, the original-reading range changes every time an original is set, thereby causing, in some cases, a difference between the set reading range and the actual receiving range. In addition, in image reading devices of a type in which an original is accommodated in an original-holder and is scanned together with the original-holder, the original moves within the original-holder, resulting in, in some cases, an operation of reading an image in an area different from the assigned area for the original.
It is an object of the present invention to assuredly receive an image within a main scanning range set after prescanning.
According to one aspect of the present invention, an image reading device having a prescanning function of reading an original in advance and a main scanning function of again reading the original after prescanning includes control means for performing control so as to perform a reading operation within a range wider than a reading range set after prescanning, at main scanning.
According to another aspect of the present invention, an image reading method applied to an image reading device having a prescanning function of reading an original in advance and a main scanning function of again reading the original after prescanning. The method includes a control step of performing control so as to perform a reading operation within a range wider than a reading range set after prescanning, at main scanning.
According to still another aspect of the present invention, in a storage medium, capable of being read by a computer, a program is stored for executing an image reading method applied to an image reading device having a prescanning function of reading an original in advance and a main scanning function of again reading the original after prescanning, the image reading method includes a control step of performing control so as to perform a reading operation within a range wider than a reading range set after prescanning, at main scanning.
According to the present invention, it is possible to assuredly receive an image within a main scanning range set after prescanning.
The foregoing and other objects, advantages and features of the present invention will become more apparent from the following description of the preferred embodiments taken in conjunction with the accompanying drawings.